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%I #12 May 15 2017 03:06:37
%S 0,0,0,5,2,4,2,9,4,8,8,11,10,12,10,15,16,18,12,21,20,20,18,25,26,28,
%T 22,27,30,30,26,41,34,36,28,51,36,42,34,55,42,48,36,65,44,52,38,77,56,
%U 56,40,81,62,58,50,87,68,64,52,93,72,66
%N a(n) + a(n-1) + a(n-2) + a(n-3) = prime(n), n>2, a(0)=a(1)=a(2)=0;.
%H G. C. Greubel, <a href="/A083241/b083241.txt">Table of n, a(n) for n = 0..1000</a>
%F A001221(a(n) - A000720(a(n))) = 1.
%F a(n) - A000720(a(n)) is in A025475.
%e a(3)+a(4)+a(5)+a(6) = 5+2+4+2 = prime(6) = 13.
%p A083241 := proc(n)
%p option remember;
%p if n <= 2 then
%p 0;
%p else
%p ithprime(n) - add(procname(n-i),i=1..3) ;
%p end if;
%p end proc: # _R. J. Mathar_, Jul 08 2012
%t Do[s=Prime[n]-n; If[Equal[Length[FactorInteger[s]], 1]&&!PrimeQ[s], Print[Prime[n]]], {n, 1, 100000}]
%t RecurrenceTable[{a[n] + a[n - 1] + a[n - 2] + a[n - 3] == Prime[n], a[0] == 0, a[1] == 0, a[2] == 0}, a, {n, 0, 50}] (* _G. C. Greubel_, May 14 2017 *)
%K nonn
%O 0,4
%A _Labos Elemer_, Apr 24 2003
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